// Tencent is pleased to support the open source community by making RapidJSON available.
//
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
//
// Licensed under the MIT License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// http://opensource.org/licenses/MIT
//
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

#ifndef RAPIDJSON_STRINGBUFFER_H_
#define RAPIDJSON_STRINGBUFFER_H_

#include "stream.h"
#include "internal/stack.h"

#if RAPIDJSON_HAS_CXX11_RVALUE_REFS
#include <utility> // std::move
#endif

#include "internal/stack.h"

#if defined(__clang__)
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(c++ 98 - compat)
#endif

RAPIDJSON_NAMESPACE_BEGIN

//! Represents an in-memory output stream.
/*!
    \tparam Encoding Encoding of the stream.
    \tparam Allocator type for allocating memory buffer.
    \note implements Stream concept
*/
template <typename Encoding, typename Allocator = CrtAllocator>
class GenericStringBuffer {
public:
	typedef typename Encoding::Ch Ch;

	GenericStringBuffer(Allocator* allocator = 0, size_t capacity = kDefaultCapacity) : stack_(allocator, capacity) {}

#if RAPIDJSON_HAS_CXX11_RVALUE_REFS
	GenericStringBuffer(GenericStringBuffer&& rhs) : stack_(std::move(rhs.stack_)) {}
	GenericStringBuffer& operator=(GenericStringBuffer&& rhs) {
		if (&rhs != this)
			stack_ = std::move(rhs.stack_);
		return *this;
	}
#endif

	void Put(Ch c) { *stack_.template Push<Ch>() = c; }
	void PutUnsafe(Ch c) { *stack_.template PushUnsafe<Ch>() = c; }
	void Flush() {}

	void Clear() { stack_.Clear(); }
	void ShrinkToFit() {
		// Push and pop a null terminator. This is safe.
		*stack_.template Push<Ch>() = '\0';
		stack_.ShrinkToFit();
		stack_.template Pop<Ch>(1);
	}

	void Reserve(size_t count) { stack_.template Reserve<Ch>(count); }
	Ch* Push(size_t count) { return stack_.template Push<Ch>(count); }
	Ch* PushUnsafe(size_t count) { return stack_.template PushUnsafe<Ch>(count); }
	void Pop(size_t count) { stack_.template Pop<Ch>(count); }

	const Ch* GetString() const {
		// Push and pop a null terminator. This is safe.
		*stack_.template Push<Ch>() = '\0';
		stack_.template Pop<Ch>(1);

		return stack_.template Bottom<Ch>();
	}

	size_t GetSize() const { return stack_.GetSize(); }

	static const size_t kDefaultCapacity = 256;
	mutable internal::Stack<Allocator> stack_;

private:
	// Prohibit copy constructor & assignment operator.
	GenericStringBuffer(const GenericStringBuffer&);
	GenericStringBuffer& operator=(const GenericStringBuffer&);
};

//! String buffer with UTF8 encoding
typedef GenericStringBuffer<UTF8<>> StringBuffer;

template <typename Encoding, typename Allocator>
inline void PutReserve(GenericStringBuffer<Encoding, Allocator>& stream, size_t count) {
	stream.Reserve(count);
}

template <typename Encoding, typename Allocator>
inline void PutUnsafe(GenericStringBuffer<Encoding, Allocator>& stream, typename Encoding::Ch c) {
	stream.PutUnsafe(c);
}

//! Implement specialized version of PutN() with memset() for better performance.
template <>
inline void PutN(GenericStringBuffer<UTF8<>>& stream, char c, size_t n) {
	std::memset(stream.stack_.Push<char>(n), c, n * sizeof(c));
}

RAPIDJSON_NAMESPACE_END

#if defined(__clang__)
RAPIDJSON_DIAG_POP
#endif

#endif // RAPIDJSON_STRINGBUFFER_H_
